Chiral Recognition Site Research Articles

Poly(α‐amino acid)‐immobilized polymer adsorbents for optical resolution. IV. Elucidation of chiral recognition mechanism of poly(N5‐benzyl‐L‐glutamine)‐immobilized resin

AbstractVarious investigations have been carried out in order to further elucidate the chiral recognition mechanism of immobilized poly(N5‐benzyl‐L‐glutamine) (PBLGN) for optical resolution. The shape and dimension of the chiral recognition site are determined by resolution of hydantoin derivatives, with substituents of varied bulkiness at the chiral center. The site of the hydrogen bonding association of the enantiomers responsible for chiral recognition is also elucidated. Several adsorbents with electron‐donating/withdrawing substituents incorporated into the PBLGN side chain phenyl are synthesized and evaluated for the resolution of (RS)‐5‐isopropylhydantoin in order to elucidate the association site of PBLGN. Based on the experimental evidences obtained, a most plausible mechanism of chiral recognition is proposed. Additionally, adsorbents with several other poly(α‐amino acid)s are also synthesized, and the effect of poly(α‐amino acid) side chain length is discussed.